1. Technical Field
The embodiments described herein generally relate to a layout structure, and more particularly to a circuit layout structure of a display.
2. Related Art
Generally, a liquid crystal display (LCD) device controls light transmittance through a liquid crystal material having a dielectric anisotropy by adjusting an electric field (to display images). The LCD device includes a LCD panel for displaying the images, and a driving circuit for driving pixel cells of the LCD panel. The driving circuit includes a gate driver for driving gate lines of the LCD panel, a source driver for driving the data lines, a timing controller for controlling drive timing of the gate driver and the source driver, and a power supply for supplying power signals required for driving the LCD panel and the driving circuit.
The source driver and the gate driver are separated into a plurality of integrated circuits (ICs) that are manufactured as semiconductor chips. Commonly, the drive IC is directly mounted onto the LCD panel using chip-on-glass (COG) technology, wherein the drive IC is directly installed onto the substrate of the LCD panel. Thus, electrical interconnection between the drive IC and the LCD panel is stable, and a relatively small pitch is acceptable for the installation of the drive IC.
In addition, a combination of COG and Wire-On-Array (WOA) technologies is used where the wiring is disposed on the glass. According to the COG and WOA technique, the IC can be directly attached to the glass substrate, and the wiring can be directly formed on the glass substrate. Accordingly, production costs can be reduced and overall size of the LCD panel can be reduced.
FIG. 1 is a plan view of a conventional LCD module. In FIG. 1, an LCD module 10 includes a glass substrate 100, and several drive ICs 101, 103, 105, 107, 109, 111, 113, and 115, preferred for source drivers. The glass substrate 100 can be made of materials used to make Thin Film Transistors (TFTs), wherein a plurality of TFTs (not shown) is arranged on a surface of the glass. The drive ICs 101, 103, 105, 107, 109, 111, 113, and 115 are disposed on the glass substrate 100 using the COG technique, wherein a die attach adhesive is disposed between the glass substrate 100 and the drive ICs 101, 103, 105, 107, 109, 111, 113, and 115. In addition, flexible printed circuit boards (FPCBs) 117 and 119 are separately disposed near the drive ICs 101, 103, 105, 107, 109, 111, 113, and 115 along a marginal area of the glass substrate 100 to transmit data signals to control the mounted drive ICs 101, 103, 105, 107, 109, 111, 113, and 115. Moreover, the LCD module 10 further includes at least a power/ground source to supply power to the drive ICs 101, 103, 105, 107, 109, 111, 113, and 115.
FIG. 2 is a partially enlarged view of the conventional LCD module of FIG. 1. In FIG. 2, the enlarged rectangle portion defined by dashed lines 15 (of FIG. 1) between drive ICs 113 and 115 includes crowded power/ground and signal lines 211, 213, 215, 217, 219, and 221 arranged on the glass substrate 100 (in FIG. 1). However, the relatively fine size of the power/ground and signal lines 211, 213, 215, 217, 219, and 221 of the drive IC is problematic.
FIG. 3 is a side view of a conventional driver circuit layout structure. In FIG. 3, drive ICs 301 and 303 (preferably source drivers) provide data signals to pixels of the LCD panel via data lines 311, 313, 315, 317, 319, 321, and 323, and 341, 343, 345, 347, 349, 351, and 353, respectively. The drive IC 301 connects to the adjacent IC 303 via lateral lines 371, 373, and 375 and/or under lines 381 and 383 for transmitting data/gamma signals. In addition, a power line 361 competes with the lateral lines 371, 373, and 375 for the limited space. In a similar way, under power lines, i.e., VGH, VGL, or Vcom lines 391, also compete with under lines 381 and 383 for the confined space.
Inevitably, the power lines 361 and 391 must be made small to allow them to fit in the space between or under the adjacent source drive IC 301 and 303, or must be decreased in number to accommodate to the overall structure. Either way, the power lines 361 and 391 are problematic because they usually cause overheating, circuit damage, explosion, and even fire. Therefore, a novel circuit layout structure of a COG display panel is needed to improve the wire configuration.